(Beyond Pesticides, November 5, 2008) The Environmental Protection Agency (EPA) acknowledged in a recent Federal Register Notice that antimicrobial pesticides in wide use are not adequately tested for their impacts on human health and the environment. Controversy surrounding the impacts of many antimicrobials in the environment has arisen in recent times to due to the prevalence of these chemicals in surface and drinking waters. Antimicrobials are defined by the EPA as ‚Äúpesticides that are intended to (1) disinfect, sanitize, reduce, or mitigate growth or development of microbiological organisms, or (2) protect inanimate objects from contamination, fouling, or deterioration caused by bacteria, viruses, fungi, protozoa, algae, or slime.‚ÄĚ For this proposal, the EPA is using the term antimicrobials to collectively refer to antimicrobial pesticides, antifoulant coatings and paints, and wood preservatives. The use of the controversial antimicrobial, triclosan, in inanimate objects, such as plastic and textiles, would be covered by these regulations, while those personal care products with the very same ingredient would not, since they fall under Food and Drug Administration authority.

In the Federal Register last month, EPA, trying to play catch-up with the science while products continue in larger and larger numbers to incorporate the controversial antimicrobials, issues new and amended data requirements that will eventually address their down the drain fate. Environmental fate data for antimicrobials dominate these new requirements, especially pertaining to the discharge of these chemicals into waste water treatment plants from household sources. Antimicrobial chemicals are regulated by the EPA under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA).
There are nine new data requirements for antimicrobial pesticides and include: photo-degradation soil studies (for wood preservatives); 2 new exposures data requirements -soil residue dissipations and non-dietary ingestion exposure; activated sludge sorption isotherm study; ready biodegradability study; porous pot study; modified activated sludge; and respiration inhibition test.

These new rules are to now be required, once accepted, along with existing requirements, some of which have been updated or now explicitly required. Four of the new data requirements will inform a screening-level assessment on the fate of antimicrobials that reach a wastewater treatment plant, according to the proposal. ‚ÄúSince many antimicrobial pesticides are typically rinsed down the drain, EPA has considered the potential impacts of pesticides that are discharged into wastewater treatment plants,‚ÄĚ it states. Along with these requirements EPA also proposes to use modeling tools such as the Down the Drain Model with the Probabilistic Dilution Model (PDM) to assist in its environmental fate screening and assessment.

The National Association of Clean Water Agencies (NACWA), a trade group for wastewater treatment plants, has long supported added scrutiny of the approval process for products regulated under FIFRA, particularly of emerging contaminants. The group is particularly concerned that the amount of antimicrobials in the wastewater stream could harm the microbes in activated sludge, which is a biological process that treatment plants use to cleanup wastewater.

‚ÄúThere are a lot of secondary contaminations that should be looked at with regard to antimicrobials in the wastewater stream.‚ÄĚ says Jay Feldman, Executive Director, Beyond Pesticides, who is supportive of the new studies in the proposed rule. but believes that the public should be warned about the data deficiencies until the chemicals are more thoroughly studied. ‚ÄúIf the agency is looking at sludge, it should also look at earthworms,‚ÄĚ which show the effects of antimicrobials on wildlife, according to Mr. Feldman.

In recent comments to the EPA for triclosan , an antimicrobial chemical, Beyond Pesticides and several other environmental and health groups criticized the EPA for not completing an analysis of the impact of triclosan on the environment, especially in the aquatic environment and endangered species, as well as other deficiencies in its review. In separate comments, waste water treatment utilities commented that triclosan and its degradation products are not cleaned out of the water treatment process and end up in sewage sludge. Research shows that earthworms take in triclosan residues, as do fish and aquatic organisms. Concerns were also been raised about residues in drinking water. A recent U.S. Geological Survey (USGS) study found that triclosan was the most detected chemical in U.S. waterways.

On November 6, 2008, EPA will convene a public workshop to explain the provisions of its recently proposed rule to update and revise the data requirements for registration of antimicrobial pesticides. The meeting will be held from 8:30 a.m. to 4:00 p.m. in the first floor conference center, One Potomac Yard (South Bldg.), 2777 S. Crystal Drive, Arlington, VA 22202. EPA has arranged for this workshop to be webcast for those who cannot attend the public workshop in person. In order for you to be able to access this webcast presentation, please read and follow all of the instructions here, well in advance of the workshop meeting.
Source: Federal Registrar, Inside EPA